Load lock devices include a load lock chamber for holding semiconductor wafers and an elevation drive unit for moving the load lock chamber up and down. The load lock chamber is vertically movable within a container. In such a device, an elevation rod is connected to a central portion of the load lock chamber. The elevation rod extends outward from a central portion of the container such that it is connected to the elevation drive unit.
In a processing system provided with a load lock device, the process must be performed in a low-impurity environment. For this reason, the load lock device must have a high degree of vacuum to reduce impurities. In order to achieve a high degree of vacuum, a large-diameter exhaust port is necessary. It is however difficult to have a large-diameter exhaust port in the container because the elevation rod is connected to the central portion of the load lock chamber. In addition, the installation of the large-diameter exhaust port may cause an increase in size of the load lock device. If a plurality of exhaust ports is used, the complexity of the device may be increased.